Hi,
My employer assigned me to do business trips abroad for about 2-3 months. Do I have to inform anyone before I leave or should I just keep all the documents regarding this and show it to the citizenship judge so my days outside canada will be counted?
Your business trip days cannot be counted as days in Canada.Business trips abroad do not count towards either your PR residency calculation or your citizenship residency calculation.
If your company had moved you to a permanent position outside of Canada (e.g. moved you to a different country for several years), then you would be able to count this time towards your PR residency requirement (but not towards citizenship).
Unfortunately business trips count as time spent outside of Canada for both PR residency and citizenship residency requirements.